The Primo Superfine, made by combining 40D ultra-fine biomass filament with polyamide filament and using a three strand composite twisting process, is the most luxurious product in its class.

The fineness of conventional biomass filament is between 100D-300D, and the fiber fineness of 40D is already the same as that of silk filament, which is currently the limit of human technology.The three strand composite twisting process has significant losses, but it can make the cross-section of the yarn closer to a perfect circle and provide a more delicate and smooth feel. It is used to create more luxurious and textured products.